How to stop K’nex motors ‘clicking’ under small loads

Written by: admin@makezilla

Picture of How to stop K'nex motors 'clicking' under small loads

Now I'm sure, if you have ever used k'nex, you will be aware of an annoying 'clicking' problem that occurs with K'nex motors. It's really annoying to build a model and find that the motor just clicks and does not operate the model. This instructable will show you a quick and simple way to solve this problem.

Let's first of all start off with why K'nex motors click. The reason is, if you try to put a motor under too much load for it to handle it will stall and eventually burn out. Obviously this is bad, and the designers of k'nex motors wanted to stop this happening. Or, at least make it so that it is apparent when a motor cannot handle a certain load. They did this by adding the 'clicking' feature. K'nex motors are, obviously, designed to be used with K'nex rods, and so they have to fit the rods. When sliding a rod through a motor's shaft, I'm sure you are aware that you have to push it quite hard to get it to go through. This is because there are two lugs of plastic that stick out and grip in the reccesses of the rods. These plastic lugs are the key to the clicking. When the motor cannot handle the load, the rod jumps round a quarter rotation and the lugs grip another part of the rod.

There is a certain load, under which the lugs do this, and this should be just before the motor would stall. The problem occures when these lugs slip too easily. This means that the motor is not performing at it's best and is being held back, in terms of torque, by these lugs.

This easy to follow, simple & easy instructable will show you how to make these lugs much strong and combat the 'clicking' problem.

Step 1: Style of motor

Picture of Style of motor

This instructable is for both the old K'nex motors and the new ones. If you have an old 'classic' motor then please go to step two, and miss out step three. If you have a newer motor then please skip step 2 and go on to step three.

Step 2: Classic motor

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This step if for the classic motors.

First of all, start by finding out which of the slots for rods is the stongest. You can do this by putting a rod in and holding it to see if you can make the motor click. If you can't and it just slides through your hand then that is a good one. If you can grip it and it clicks then it is a bad one. Then you need to think about which slot you use most.

Now, remove the srews. These are all the same length so you do not need to pay any attention as to where they go. When the screws are all removed, carefully lift off the top casing. Be careful to make sure that all the gears do not come loose and fall apart. Make sure not to accidently turn on the motor, when it is in this state, as this can damadge it. When the case is removed lift out the large main gear on top. This may come off in several peices so make sure to remove them all. Now, go ahead and remove the second smaller gear which is horizontally postitioned. Again, this may come out in several peices so take care.

You will notice a spring around each set if lugs. These springs are what pushes the lugs down on the rods. What you need to do is swap the springs around so that the strong one is on the slot that you use most. Now, I know that this means not all will be strong, but that is why you need to think about which slot you most use.

Place the smaller gear in first and then the bigger gear. Then put the case back and do up all the screws.

Step 3: Newer motor

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This step if for the newer motors.

First of all, start by finding out which of the slots for rods is the stongest. You can do this by putting a rod in and holding it to see if you can make the motor click. If you can't and it just slides through your hand then that is a good one. If you can grip it and it clicks then it is a bad one. Then you need to think about which slot you use most.

Now, before remove all the screws that hold on the casing, you want to run a sharp knife through the black bit where the power cables run. Be careful not to cut the wires though. Then you can remove the srews. These are all the same length so you do not need to pay any attention as to where they go. When the screws are all removed, carefully lift off the top casing. Be careful to make sure that all the gears do not come loose and fall apart. Make sure not to accidently turn on the motor, when it is in this state, as this can damadge it. When the case is removed lift out the large main gear on top. This may come off in several peices so make sure to remove them all. Now, go ahead and remove the second smaller gear which is horizontally postitioned. Again, this may come out in several peices so take care.

You will notice a spring around each set if lugs. These springs are what pushes the lugs down on the rods. What you need to do is swap the springs around so that the strong one is on the slot that you use most. Now, I know that this means not all will be strong, but that is why you need to think about which slot you most use.

When putting the gears back together, make sure to put the right cap with the right gear, as the are differnt lenghs and will not fir with eachother. Place the smaller gear in first and then the bigger gear. Then put the case back and do up all the screws.

 

Step 4: Enjoy your fine work

Now you can build more eleborate and complex models than before, with motors that will be able to do more than before.

Also, you may want to think about these other few things that can help with 'clicking' motors:

1) Rods. The clicking process slowly wears away the rods. I recomend using rods like the grey speckled one instead of the yellow ones, the dark black ones rather than the grey or orange ones. As for all the other colour variations, they are the same. The reason the colour makes a differnce with these two examples, is that they are harder than the other ones, as they are darker, because they have a higher carbon content. Especially the black ones.

2) Friction. Obviously the more friction there is, the harder it is for the electric motor to turn all those gears inside the case, and the harder it is having to work, and so the less power you will get and the more likely it is to click. I would recomend some light grease such as Vaseline. Apply a small dab on each gear and the one it meshes with, the motor and all the spindles, and it should improve the running. It will also make it quieter if you have a noisy one.

3) Gearing. Whatever you make, however complex will need to have the right gearing. Make sure you have the right gearing so the motor will cope, otherwise it is obviously going to fail and click.

4) Don't expect too much. These K'nex motors are quite powerful, but don't expect them to be able to do stuff they can't. The clicking is there to tell you that you have maxed out the motors capabilities.

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